This car has the unexplained "wash me" sign clearly imprinted on its rear hatch.

"You don't see dirty children with 'wash me' messages carved into their foreheads," said Crystal Klucher, a paranormal investigator who has theorized that Stonehenge was a Roman drive-thru restaurant for charioteers on the go. "You don't see cryptic messages appearing on a mechanic’s oil-stained coveralls, or branded on the family dog. It seems to be a localized phenomenon confined to the backs, sides, and windshields or cars, trucks, delivery vans, and other dirt-encrusted automobilia."

Crystal has refutable evidence that many automobile engines vibrate at the same frequency as the 9th Dimension, and that idling vehicles act as impromptu portal gateways to this other plane of existence. Crystal argues that the dirt acts as a communications medium, and that higher beings of pure light and cleanliness communicate harmonically to those of us stuck on the third dimension through signs on back windows, bumpers, or wherever enough dirt accumulates.

"It’s even happened to me,” said Crystal. “I woke up early one morning and, sensing something was wrong, I went straight to my Sebring. There, scrawled on the passenger-side door were the words 'wash me', with a happy face right underneath it.”

This earthy message is very common on the back sliding doors of delivery trucks, sometimes with the word "please" amended to the end of the message. Other variations have been seen: I need washing, wash time, or I'm dirty. True numbers of this paranormal phenomenon are not known. People are either too afraid or embarrassed to come forward and admit it has happened to them.